REPORT OF COMMISSIONER OF FIS?I AND FISHERIES. 55 



Washington, I). C, the Potomac River, creeks in Virginia accessible 

 to the station by wagon, and IVoin Fort Washington Station, Md. 



Spawning was observed in the fresli-water aqnaria, as follows : YeUow 

 percli, fifteen deposits of eggs from December to April, inclusive; three 

 mussels in March and April; rainbow and tessellated darters in April, 

 Yearling rainbow trout were held through the month of May in a tem- 

 perature of 72° to 70° F. 



In the salt water a rainbow trout spawned in March, 1890, after hav- 

 ing dei)osited eggs a month previous in freshwater; several nests were 

 built by the two-si»ined stu'klebacks in April and May; several common 

 killifish spawned in April; and in June king crab eggs were received 

 and hatched^ From unknown causes mollusca, hermit-crabs, anemones, 

 starfish, and sea-urchins could not be successfully kept. 



Colored and plain sketches were made by Mr. S. F. Denton illustrat- 

 ing the spawning habits of nnissels and of rainbow and tessellated 

 darters. 



1890-91. 



Two collecting trips were made down the Chesapeake Bay, and 

 specimens were also obtained from Woods Holl Station, Cold Spring- 

 Harbor, and from other sources through the distribution cars. Young 

 shad, 3 to -t inches long, received from the tish ponds, Washington, 

 D. C, in October, 1890, were with partial success held in the salt-water 

 aquaria, Atlantic and qninnat salmon, and rainbow, brook, and lake 

 trout yearlings were successfully kept in the salt water. About No- 

 vember 1, 1890, a large female skate was received and placed in a salt- 

 water tank; in January several eggs were deposited, which, on May 

 12, were found to contain living embryos. Both the common newt and 

 top-minnow reproduced in April in fres^^ water. 



In December, 1890, the salt-water temperature fell to 48° F,, when 

 artificial heat was introduced into the tank room, which maintained a 

 temperature of 50° to 54° during the remainder of the winter. In June 

 the temperature went up to 80°. 



Steamer Fish Hawk (Lieut. Roueiit Platt, U. S. N., Commaxdixg). 



1889-90. 



After the establishment of the shore station at Gloucester City the 

 Fish Haivkj as in previous years, entered upon theproi)agation of shad 

 on the Delaware Kiver. The vessel was anchored olf Gloucester, the 

 water supply used in hatching operations iK'ing taken directly from the 

 river. The crew began taking eggs April 30, using the launch Petrel. 

 The river temperature was r)7° F. liy May 15 the water had risen to 

 G3°, Avhen the collections of v^j^i^v. amounted to 27,234,000. On May 23 

 they amounted to 33,915,000, when the work closed, the temperature 

 being 04°. There were produced 20,590,000 fry, which were liberated 



